JP6196838B2 - Optical fiber cable and intermediate post-branching method of optical fiber cable - Google Patents

Description

  The present invention relates to an optical fiber cable and an intermediate post branching method for an optical fiber cable.

  In an optical fiber cable, a structure in which a tear string (lip cord) is embedded in the cable is known in order to facilitate an optical fiber lead-out operation at the time of intermediate post branching (see, for example, Patent Documents 1 to 3). In this structure, it is necessary to scrape the jacket in order to take out the lip cord, and the workability is poor. Furthermore, since the blade for scraping the jacket is inserted to the vicinity of the optical fiber, the optical fiber may be damaged. In order to prevent damage to the optical fiber, it is necessary to adjust the blade with high accuracy, and an expensive tool is required.

JP 2010-204368 A JP 2002-107591 A JP 2010-204368 A

  For this reason, it is required that the optical fiber can be easily and safely extracted without using an expensive tool. This requirement is particularly high in a retractable cable (drop cable) that requires quick workability.

  An object of the present invention is to provide an optical fiber cable and an optical fiber cable intermediate post-branching method that can easily and safely carry out an optical fiber lead-out operation.

  According to one aspect of the present invention, an optical fiber, a cylindrical member made of plastic that covers the periphery of the optical fiber, and a fibrous plastic or glass fiber that is disposed around the cylindrical member and impregnated with resin. An optical fiber cable is provided that includes an inclusion, a cylindrical member and a jacket that covers the periphery of the inclusion, and a tensile body made of a pair of reinforcing fiber plastics embedded in the jacket with the optical fiber interposed therebetween.

  According to another aspect of the present invention, a fiber, a cylindrical member made of plastic covering the periphery of the optical fiber, and an inclusion made of fibrous plastic or glass fiber disposed around the cylindrical member; An optical fiber cable comprising a plastic film covering the periphery of an inclusion, a jacket covering the periphery of a cylindrical member, and a tensile body made of a pair of reinforcing fiber plastics embedded in the jacket across the optical fiber is provided. Is done.

In one embodiment and other embodiments of the present invention, the cross section of the inclusion perpendicular to the cable longitudinal direction is elliptical, the long diameter of the inclusion is w1, the diameter of the cylindrical space inside the jacket is D1, and the cylindrical shape The outer diameter of the member is D2, the number of inclusions is n, and the minor axis t1 of the inclusion is t1 = (D1-D2) / 2
And the circumferential length L1 of the circle formed by the inclusions in the cross section perpendicular to the cable longitudinal direction,
L1 = (t1 + D2) × π
When stipulating
L1> w1 × n> D2 × π
May be satisfied.

  In one embodiment and other embodiments of the present invention, a plurality of protrusions may be formed inside the outer jacket.

  In one aspect and other aspects of the present invention, the cross section of the inclusion perpendicular to the cable longitudinal direction is substantially elliptical, and two protrusions out of the plurality of protrusions are at positions facing each other across the optical fiber, The sum of the gaps between the two protrusions and the cylindrical member may be smaller than the minor axis of the inclusion.

  In one embodiment and other embodiments of the present invention, two of the plurality of protrusions may be provided on a straight line connecting the pair of strength members.

  In one embodiment and other embodiments of the present invention, the cylindrical member may be either a plastic tube and a plastic tape that is vertically or roughly wound.

  In one embodiment and other embodiments of the present invention, the inclusions may have higher heat resistance than the outer shell.

  In one embodiment and other embodiments of the present invention, a plurality of inclusions may be arranged.

  According to still another aspect of the present invention, an optical fiber, a cylindrical member made of plastic covering the periphery of the optical fiber, and a fibrous plastic or glass fiber disposed around the cylindrical member and impregnated with a resin An intermediate post of an optical fiber cable comprising an inclusion made of, a cylindrical member and a jacket covering the periphery of the inclusion, and a tensile body made of a pair of reinforcing fiber plastics embedded in the jacket with the optical fiber interposed therebetween A bifurcation method, the step of inserting a blade into the jacket; and the step of cutting the tensile body and turning the jacket into a ring by rotating the blade inserted into the jacket in the circumferential direction. A method for intermediate post-branching of an optical fiber cable is provided.

  According to still another aspect of the present invention, an optical fiber, a cylindrical member made of plastic covering the periphery of the optical fiber, and an inclusion made of fibrous plastic or glass fiber disposed around the cylindrical member; The outer cover covering the periphery of the cylindrical member and the inclusion, the plastic film disposed between the inclusion and the outer cover, and a pair of reinforcing fiber plastics embedded in the outer cover with the optical fiber interposed therebetween An intermediate post-branching method of an optical fiber cable comprising a tensile body, the step of inserting a blade into the outer sheath, and cutting the tensile body by rotating the blade inserted into the outer sheath in the circumferential direction of the outer sheath. And an intermediate post-branching method for an optical fiber cable, comprising the steps of:

  According to the present invention, it is possible to provide an optical fiber cable and an optical fiber cable intermediate post-branching method capable of easily and safely performing an optical fiber lead-out operation.

It is sectional drawing perpendicular | vertical to the cable longitudinal direction which shows an example of the optical fiber cable which concerns on the 1st Embodiment of this invention. It is sectional drawing for demonstrating an example of the extraction method of the optical fiber cable which concerns on the 1st Embodiment of this invention. It is sectional drawing perpendicular | vertical to the cable longitudinal direction which shows the optical fiber cable which concerns on the Example of the 1st Embodiment of this invention. It is a perspective view which shows the mode at the time of the lead-out | work work of the optical fiber cable which concerns on the Example of the 1st Embodiment of this invention. It is sectional drawing perpendicular | vertical to the cable longitudinal direction which shows an example of the optical fiber cable which concerns on the 2nd Embodiment of this invention. It is sectional drawing perpendicular | vertical to the cable longitudinal direction which shows an example of the optical fiber cable which concerns on the 3rd Embodiment of this invention. It is sectional drawing perpendicular | vertical to the cable longitudinal direction for demonstrating the bending of the optical fiber cable which concerns on the 3rd Embodiment of this invention. It is sectional drawing perpendicular | vertical to a cable longitudinal direction when the center core of the optical fiber cable which concerns on the 3rd Embodiment of this invention is eccentric. It is sectional drawing perpendicular | vertical to the cable longitudinal direction which shows an example of the optical fiber cable which concerns on the 4th Embodiment of this invention. It is sectional drawing perpendicular | vertical to the cable longitudinal direction which shows an example of the optical fiber cable which concerns on the 5th Embodiment of this invention. It is sectional drawing perpendicular | vertical to the cable longitudinal direction which shows an example of the optical fiber cable which concerns on the 6th Embodiment of this invention. It is sectional drawing perpendicular | vertical to the cable longitudinal direction which shows an example of the optical fiber cable which concerns on other embodiment of this invention.

  At least the following matters will be apparent from the description and drawings described below.

  An optical fiber, a cylindrical member made of plastic covering the periphery of the optical fiber, an inclusion made of fibrous plastic or glass fiber disposed around the cylindrical member and impregnated with resin, and the cylindrical member and the intermediate An optical fiber cable comprising an outer sheath covering the periphery of an object and a strength member made of a pair of reinforcing fiber plastics embedded in the outer sheath with the optical fiber interposed therebetween is clarified. With such an optical fiber cable, it is possible to cut the strength member together with the outer cover, so that it is possible to easily perform the opening work and to safely cut the outer cover by interposing an inclusion. It becomes possible.

  Further, a fiber, a cylindrical member made of plastic covering the periphery of the optical fiber, an inclusion made of fibrous plastic or glass fiber arranged around the cylindrical member, and the periphery of the cylindrical member and the inclusion A covering film, a plastic film disposed between the inclusion and the covering, and a tensile body made of a pair of reinforcing fiber plastics embedded in the covering with an optical fiber interposed therebetween. The fiber optic cable becomes clear. With such an optical fiber cable, it is possible to cut the strength member together with the outer cover, so that it is possible to easily perform the opening work and to safely cut the outer cover by interposing an inclusion. It becomes possible.

In addition, the cross section perpendicular to the cable longitudinal direction of the inclusion is elliptical, the long diameter of the inclusion is w1, the diameter of the cylindrical space inside the jacket is D1, the outer diameter of the cylindrical member is D2, and the inclusion And the minor axis t1 of the inclusion is t1 = (D1-D2) / 2
And the circumferential length L1 of the circle formed by the inclusions in the cross section perpendicular to the cable longitudinal direction,
L1 = (t1 + D2) × π
When stipulating
L1> w1 × n> D2 × π
It is desirable to satisfy the relationship. Thereby, the eccentricity of an optical fiber and a cylindrical member can be avoided, and favorable wicking property can be maintained.

  In addition, it is desirable that a plurality of protrusions be formed on the inner side of the jacket. Thereby, the movement to the bending inner side of the inclusion at the time of bending a cable can be suppressed.

  Further, the cross section of the inclusion perpendicular to the longitudinal direction of the cable is substantially elliptical, and two of the plurality of protrusions are in positions facing each other across the optical fiber, and each of the two protrusions and the cylindrical member Is preferably smaller than the minor axis of the inclusion. Thereby, the movement to the bending inner side of the inclusion at the time of bending a cable can be suppressed more reliably.

  Moreover, it is desirable that two of the plurality of protrusions are provided on a straight line connecting the pair of strength members. Thereby, the movement to the bending inner side of the inclusion at the time of bending a cable can be suppressed effectively.

  Moreover, it is desirable that the cylindrical member is either a plastic tube and a plastic tape vertically or roughly wound. Thereby, since the optical fiber is protected by the cylindrical member in the state of being punctured, it is possible to safely perform the work after the wicking.

  Moreover, it is desirable that the heat resistance of the inclusion is higher than the heat resistance of the jacket. Thereby, melting and deformation of inclusions due to heat at the time of extruding the jacket can be prevented.

  Moreover, it is desirable that a plurality of inclusions are arranged. Thereby, a cylindrical member can be arrange | positioned more centrally in the cross section perpendicular | vertical to a cable longitudinal direction.

  Further, an optical fiber, a cylindrical member made of plastic covering the periphery of the optical fiber, an inclusion made of fibrous plastic or glass fiber disposed around the cylindrical member and impregnated with resin, and the cylindrical member And an intermediate post-branching method for an optical fiber cable comprising a jacket covering the periphery of an inclusion, and a tensile body made of a pair of reinforcing fiber plastics embedded in the jacket with the optical fiber interposed therebetween, An optical fiber cable comprising: a step of inserting a blade; and a step of cutting the strength member and cutting the outer cover into a ring by rotating the blade inserted into the outer cover in a circumferential direction. The intermediate post-branching method becomes clear. With such an intermediate post-branching method of the optical fiber cable, the strength member can be cut together with the outer cover, so that the lead-out operation can be easily performed and the inclusion can be interposed to interpose the outer cover. Can be safely cut.

  Also, an optical fiber, a cylindrical member made of plastic covering the periphery of the optical fiber, an inclusion made of fibrous plastic or glass fiber disposed around the cylindrical member, and the periphery of the cylindrical member and the inclusion An optical fiber cable comprising: a jacket covering the outer wall; a plastic film disposed between the inclusion and the jacket; and a tensile body made of a pair of reinforcing fiber plastics embedded in the jacket with the optical fiber interposed therebetween. An intermediate post-branching method, a step of inserting a blade into the outer cover, and a step of cutting the tensile body and turning the outer cover into a ring by rotating the blade inserted in the outer cover in the circumferential direction An intermediate post-branching method of an optical fiber cable characterized by including: With such an intermediate post-branching method of the optical fiber cable, the strength member can be cut together with the outer cover, so that the lead-out operation can be easily performed and the inclusion can be interposed to interpose the outer cover. Can be safely cut.

  Next, first to sixth embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

(First embodiment)
As shown in FIG. 1, the optical fiber cable according to the first embodiment of the present invention includes an optical fiber 1, a cylindrical member 2 made of plastic covering the periphery of the optical fiber 1, and a periphery of the cylindrical member 2. Between the cylindrical member 2 and the jacket 5, a jacket 5 that covers the optical fiber 1, a pair of strength members 6 a and 6 b made of reinforcing fiber plastic (FRP) embedded in the jacket 5 with the optical fiber 1 interposed therebetween And inclusions 3a to 3d made of fibrous plastic or glass fiber.

  In the first embodiment of the present invention, the number and type of optical fibers 1 are not particularly limited. As the optical fiber 1, a core wire such as an optical fiber strand, an optical fiber core wire, or an optical fiber tape core wire can be employed. Among these, as the optical fiber ribbon, an intermittently fixed ribbon or the like can be used. Moreover, when it has the several optical fiber 1, it may extend | stretch in parallel with a cable longitudinal direction, without twisting, may be twisted in one direction, may be twisted in SZ shape, and is one way A composite shape in which the twist and the SZ twist are interchanged in the middle may be maintained. In addition, a plurality of optical fiber units in which a plurality of optical fibers 1 are mounted may be mounted in the cylindrical member 2.

  As the cylindrical member 2 made of plastic, it is possible to use a plastic tube (so-called loose tube) or a plastic tape that is roughly wound or vertically attached. As the plastic, thermoplastic resins such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT) or nylon (registered trademark), or thermosetting resins such as epoxy can be used. is there. Moreover, the space | gap may be provided inside the cylindrical member 2, and fillers, such as jelly which consists of PBT, may be filled in the space | gap.

  Although FIG. 1 shows a case where four inclusions 3 a to 3 d are spirally wound around the outer periphery of the cylindrical member 2, the inclusions 3 a to 3 d may be vertically attached to the outer periphery of the cylindrical member 2. Good. When the inclusions 3a to 3d are spirally wound, the cylindrical member 2 is arranged at the center in the cross section perpendicular to the longitudinal direction of the cable, so that the lead-out operation can be performed with high reliability. . The inclusions 3a to 3d may be in contact with each other, or may be spaced apart at equal intervals or different intervals. In FIG. 1, the inclusions 3 a to 3 d are separated from the jacket 5, but the inclusions 3 a to 3 d may be in contact with the jacket 5.

  The number of inclusions 3a to 3d is not particularly limited, and may be one. In addition, when the number of the inclusions 3a-3d is one, it is necessary to wrap around the outer periphery of the cylindrical member 2 spirally. If there are a plurality of inclusions 3a to 3d, the cylindrical member 2 can be arranged at the center in a cross section perpendicular to the cable longitudinal direction.

  The thickness of the inclusions 3a to 3d is about 1500 to 5000 denier. The inclusions 3a to 3d have, for example, a substantially elliptical cross-sectional shape, and the major axis w1 is about 2.0 mm to 2.5 mm, and the minor axis t1 is about 0.4 mm to 0.5 mm. The inclusions 3a to 3d may have other cross-sectional shapes such as a substantially circular shape.

  As the inclusions 3a to 3d made of fibrous plastic, for example, plastic yarn such as PP yarn can be used. Further, as the inclusions 3a to 3d made of glass fiber, a general glass yarn can be used. The heat resistance of the inclusions 3a to 3d is preferably higher than the heat resistance of the jacket 5. Thereby, the fusion | melting and deformation | transformation of the inclusions 3a-3d by the heat | fever at the time of extrusion of the outer jacket 5 can be prevented. In addition, the inclusions 3a to 3d are impregnated with a resin such as urethane, so that the fluffing of the fibers is suppressed and integrated while having flexibility.

  As the material of the outer cover 5, a resin such as polyvinyl chloride (PVC), polyethylene (PE), nylon (registered trademark), ethylene fluoride, or polypropylene (PP) can be used.

  As the FRP constituting the strength members 6a and 6b, an aramid fiber reinforced plastic (AFRP) reinforced with an aramid fiber such as Kevlar (registered trademark), a glass fiber reinforced plastic (GFRP), or the like can be used.

  Next, an example of the intermediate post-branching method (outlet method) of the optical fiber cable according to the first embodiment of the present invention will be described. As a tool used in the optical fiber lead-out operation, it is preferable that the depth of insertion into the blade jacket 5 can be adjusted and a guide is provided at a position facing the blade. Specifically, a coaxial cable stripper CCS-600 manufactured by Jeffcom Co., Ltd., a coaxial cable stripper manufactured by IDEAL, or the like can be used.

  (A) As shown in FIG. 2, the tool blade 7 is inserted into the jacket 5. Here, it is preferable to adjust the length d1 inserted into the jacket 5 of the tool blade 7 so as to be smaller than the minor axis t1 of the inclusions 3a to 3d.

  (B) The tool blade 7 is rotated in the direction of the arrow while keeping the insertion length d1 of the tool blade 7 constant, and the tensile strength members 6a and 6b are cut and the jacket 5 is cut into a ring. To do. At this time, since the tool blade 7 does not reach the optical fiber 1 and the cylindrical member 2, damage to the optical fiber 1 and the cylindrical member 2 can be prevented.

  (C) Further, use a tool to cut another part of the optical fiber cable, cut the outer cover 5 between the two cut parts in the cable longitudinal direction, and strip off a part of the outer cover 5 Speak out. Thereafter, the cylindrical member 2 is opened and the optical fiber 1 is taken out.

  Next, an example of the manufacturing method of the optical fiber cable according to the first embodiment of the present invention will be described. First, the loose tube 2 is produced by extruding a resin filled with jelly on the optical fiber 1. Then, inclusions 3a to 3d impregnated with a resin such as urethane are wound around the loose tube 2 in a spiral shape. The member wound with the inclusions 3a to 3d is introduced into the extruder together with the strength members 6a and 6b. Resin is extruded by an extruder to form a jacket 5. As a result, the optical fiber cable shown in FIG. 1 is completed.

  According to the optical fiber cable according to the first embodiment of the present invention, the strength members 6a and 6b are embedded in the outer sheath 5, and the FRP is used as the strength members 6a and 6b. Since the tensile strength members 6a and 6b can be collectively cut together with the outer cover 5, it is possible to easily perform the mouth-out operation.

  Further, by interposing the inclusions 3a to 3d between the cylindrical member 2 and the jacket 5, the jacket 5 is cut by the tool blade 7 without damaging the optical fiber 1 and the cylindrical member 2. Is possible.

  Moreover, since the optical fiber 1 is protected by the cylindrical member 2 in the extracted state by having the cylindrical member 2, it is possible to safely perform operations such as housing in a cabinet.

Moreover, since the inclusions 3a to 3d are impregnated with a resin such as urethane, fuzz of fibers constituting the inclusions 3a to 3d can be suppressed. As a result, it is possible to avoid the inclusions 3 a to 3 d from being heat-sealed to the outer cover 5 during the extrusion molding of the resin that becomes the outer cover 5.
<Example>
As an optical fiber cable according to the example of the first embodiment of the present invention, an optical fiber cable having a structure as shown in FIG. 3 was produced. That is, a cylindrical member (loose tube) 2 filled with jelly made of PBT was extruded on the optical fiber 1 to obtain an outer diameter of 1.9 mm. Around the periphery, three glass fiber bundles of 1500 denier impregnated with urethane were wound as inclusions 3a to 3c. Around the periphery, two glass FRPs having a diameter of 0.7 mm were embedded as tensile strength members 6a and 6b in a sheath 5 made of linear low density polyethylene (LLDPE) in parallel. The inner diameter of the jacket 5 is 2.8 mm, the outer diameter is 5.4 mm, and the thickness is 1.3 mm.

  The produced optical fiber cable was subjected to an extraction operation using a coaxial cable stripper manufactured by IDEAL as an extraction tool. At this time, the length inserted into the outer jacket 5 of the blade was adjusted to 1.5 mm.

  As a result of the lead-out operation, it was possible to easily cut the outer jacket 5 in the circumferential direction together with the strength members 6a and 6b made of glass FRP. Moreover, as shown in FIG. 4, the inclusions 3a to 3c and the loose tube 2 were left, and extraction of 1 m or more was easily possible. Further, no scratch was observed on the surface of the cylindrical member 2 taken out.

  On the other hand, as a first comparative example, an optical fiber cable having the same structure as that of the example was manufactured except that a steel wire having a diameter of 0.7 mm was used as a strength member. In the first comparative example, since the tensile strength member cannot be cut, it is impossible to squeeze out as in the example.

  Further, as a second comparative example, an optical fiber cable having the same structure as that of the example was manufactured except that the inclusions were not impregnated with resin such as urethane. In the second comparative example, fine glass fibers of inclusions were thermally fused with the resin at the time of extrusion molding of the resin serving as the jacket. As a result, the outer envelope embedded with FRP could be cut, but the outer envelope could not be pulled out.

(Second Embodiment)
As shown in FIG. 5, the optical fiber cable according to the second embodiment of the present invention has a plastic film 4 vertically attached between the inclusions 3a to 3d and the jacket 5 in the longitudinal direction of the cable. The point which the objects 3a-3d are not impregnated with resin, such as urethane, differs from the optical fiber cable shown in FIG.

  The material of the plastic film 4 is a thermoplastic resin such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT) or nylon (registered trademark), or a thermosetting resin such as epoxy. Can be used.

  Since the other configuration of the optical fiber cable according to the second embodiment of the present invention is the same as that of the first embodiment, the redundant description is omitted.

  According to the optical fiber cable according to the second embodiment of the present invention, as in the first embodiment, the strength members 6a and 6b are embedded in the outer jacket 5, and the strength members 6a and 6b are used. By using the FRP, the tensile strength members 6a and 6b can be cut together with the outer cover 5 at the time of the extraction work, so that the extraction work can be easily performed.

  Further, by disposing the plastic film 4 between the inclusions 3a to 3d and the outer cover 5, the outer cover 5 and the inclusions 3a to 3d are fused by heat when the outer cover 5 is pushed out. Can be prevented. Therefore, it is not necessary to impregnate the inclusions 3a to 3d with a resin such as urethane as in the first embodiment. The inclusions 3a to 3d may be impregnated with a resin such as urethane.

  At the time of intermediate post branching of the optical fiber cable according to the second embodiment of the present invention, the length of the blade of the tool inserted inside the jacket 5 is set to the thickness of the plastic film 4 and the shortness of the inclusions 3a to 3d. It is preferable to adjust so that it may become smaller than the sum with diameter t1. The plastic film 4 can be cut together with the strength members 6 a and 6 b and the outer cover 5.

  In addition, in the method of manufacturing the optical fiber cable according to the second embodiment of the present invention, after the inclusions 3a to 3d are spirally wound around the loose tube 2, the periphery is covered with the plastic film 4. The difference from the first embodiment of the present invention is that it is introduced into the extruder. Since other procedures are the same as those of the first embodiment of the present invention, a duplicate description is omitted.

<Example>
An optical fiber cable according to the second embodiment of the present invention was produced as follows. A cylindrical member (loose tube) 2 filled with jelly made of PBT was extruded on the optical fiber 1 to obtain an outer diameter of 1.9 mm. Around the periphery, three 3000 denier PP yarns were wound as inclusions 3a to 3c, and then a PET film having a thickness of 0.025 mm was vertically attached as the plastic film 4. Around the periphery, two glass FRPs having a diameter of 0.7 mm were embedded as tensile strength members 6a and 6b in a sheath 5 made of linear low density polyethylene (LLDPE) in parallel. The inner diameter of the jacket 5 is 2.8 mm, the outer diameter is 5.4 mm, and the thickness is 1.3 mm.

  The produced optical fiber cable was subjected to an extraction operation using a coaxial cable stripper manufactured by IDEAL as an extraction tool. At this time, the length inserted into the outer jacket 5 of the blade was adjusted to 1.5 mm.

  As a result of the lead-out operation, it was possible to easily cut the outer jacket 5 in the circumferential direction together with the strength members 6a and 6b made of glass FRP. Further, the inclusions 3a to 3c and the loose tube 2 were left, and the extraction of 1 m or more was easily possible. Further, no scratch was observed on the surface of the cylindrical member 2 taken out.

  On the other hand, as a first comparative example, an optical fiber cable having a structure identical to that of the example was manufactured except that a steel wire having a diameter of 0.7 mm was used as the strength members 6a and 6b. In the first comparative example, the tensile strength members 6a and 6b cannot be cut, so that the extraction as in the example is impossible.

  Further, as a second comparative example, an optical fiber cable having the same structure as that of other members and dimensions was manufactured except that the plastic film 4 was not used. In the second comparative example, the PP yarn was fused with the jacket by heat during extrusion molding of the resin serving as the jacket. As a result, the outer envelope embedded with FRP could be cut, but the outer envelope could not be pulled out.

(Third embodiment)
As shown in FIG. 6, the optical fiber cable according to the third embodiment of the present invention has the long diameter of inclusions 3a to 3d whose cross section perpendicular to the longitudinal direction of the cable is elliptical, w1 and the inside of the jacket 5 The diameter of the cylindrical space (in the third embodiment of the present invention, the inner diameter of the jacket 5) is D1, the outer diameter (center core diameter) of the cylindrical member 2 is D2, and the inclusions 3a to 3d N is the number, and the minor axis t1 of the inclusions 3a to 3d is t1 = (D1-D2) / 2 (1)
And the circumferential length L1 of the circle formed by the inclusions 3a to 3d in the cross section perpendicular to the cable longitudinal direction,
L1 = (t1 + D2) × π (2)
When the following formula is established: L1> w1 × n> D2 × π (3)
The first embodiment of the present invention is that the dimensions of the inclusions 3a to 3d, the jacket 5 and the cylindrical member 2 and the number of the inclusions 3a to 3d are defined so as to satisfy the above relationship. And different.

  Since the other configuration of the optical fiber cable according to the third embodiment of the present invention is the same as that of the first embodiment of the present invention, the redundant description is omitted.

  Here, as shown in FIG. 7, when the inclusions 3a to 3d are vertically attached to the cylindrical member 2, when the cable is bent with the straight line L0 connecting the strength members 6a and 6b as a neutral line, Due to the bending strain, the inclusions 3a to 3d may approach one side (bending side) as shown in FIG. As a result, it is conceivable that the cylindrical member 2 is eccentric and damages the cylindrical member 2 and the optical fiber 1 when the outer sheath 5 is cut.

  On the other hand, according to the third embodiment of the present invention, by defining each dimension so as to satisfy the above formula (3), inclusions 3a to 3d are bent inside when the cable is bent. It can suppress entering. Further, even when the inclusions 3a to 3d approach the bending inner side, the gap formed when the inclusions 3a to 3d approach is sufficiently smaller than the outer diameter (center core diameter) D2 of the cylindrical member 2, so that the optical fiber The eccentricity of the central core composed of 1 and the cylindrical member 2 can be avoided. Accordingly, it is possible to maintain a good mouth-out property.

<Example>
As an example according to the third embodiment of the present invention, an optical fiber cable having the same structure as that of the example of the first embodiment of the present invention was produced. At that time, the inner diameter D1 of the jacket 5 was 2.8 mm, and the outer diameter (center core diameter) D2 of the cylindrical member 2 was 1.9 mm so as to satisfy the above formula (3). In addition, the number n of inclusions was 3, the three inclusions having a major axis w1 of 2.2 mm and a minor axis of 0.5 mm were impregnated with urethane, and the minor axis t1 after urethane impregnation was 0.45 mm. As a result of performing the lead-out operation on the manufactured optical fiber cable, it was confirmed that uneven thickness of the central core was avoided and good lead-out property could be maintained.

(Fourth embodiment)
In the optical fiber cable according to the fourth embodiment of the present invention, as shown in FIG. 9, a plastic film 4 is vertically attached between the inclusions 3a to 3d and the jacket 5 in the longitudinal direction of the cable. The point which the thing 3a-3d is not impregnated with resin, such as urethane, differs from the 3rd Embodiment of this invention.

  In the fourth embodiment of the present invention, the major axis of the inclusions 3a to 3d whose cross section perpendicular to the cable longitudinal direction is elliptical is w1, and the diameter of the cylindrical space inside the jacket 5 (the first of the present invention In the fourth embodiment, the value obtained by subtracting the thickness of the plastic film 4 from the inner diameter of the outer cover 5) is D1, the outer diameter (central core diameter) of the cylindrical member 2 is D2, and the inclusions 3a to 3d The minor axis t1 of the inclusions 3a to 3d is defined by the above formula (1), where n is the number, and the inclusions 3a to 3d pass through the center of the inclusions 3a to 3d in a cross section perpendicular to the cable longitudinal direction. When the circumference L1 of the circle is defined by the above formula (2), the dimensions of the inclusions 3a to 3d, the jacket 5 and the cylindrical member 2 and the inclusion so as to satisfy the relationship of the above formula (3) The number of 3a-3d is prescribed | regulated.

  Since the other configuration of the optical fiber cable according to the fourth embodiment of the present invention is the same as that of the third embodiment of the present invention, the redundant description is omitted.

  According to the fourth embodiment of the present invention, by defining each dimension so as to satisfy the above formula (3), the inclusions 3a to 3d are prevented from entering the inside of the bend when the cable is bent. be able to. Further, even when the inclusions 3a to 3d approach the bending inner side, the gap formed when the inclusions 3a to 3d approach is sufficiently smaller than the outer diameter (center core diameter) D2 of the cylindrical member 2, so that the optical fiber The eccentricity of the central core composed of 1 and the cylindrical member 2 can be avoided. Accordingly, it is possible to maintain a good mouth-out property.

(Fifth embodiment)
As shown in FIG. 10, the optical fiber cable according to the fifth embodiment of the present invention is characterized in that a plurality of protrusions 5a and 5b are formed inside the outer jacket 5, Different from the embodiment.

  The lengths (heights) h1 and h2 protruding from the inner wall surface of the outer jacket 5 of the protrusions 5a and 5b are, for example, about 0.3 mm to 0.5 mm, and may be the same or different.

  The protrusions 5a and 5b are arranged at positions facing each other on a straight line connecting the strength members 6a and 6b. Thereby, when the cable is bent, since the straight line connecting the strength members 6a and 6b becomes a bending neutral line, the movement of the inclusions 3a and 3b to the inside of the bending can be effectively suppressed.

  The sum (c1 + c2) of gaps (clearances) c1 and c2 formed between the protrusions 5a and 5b and the cylindrical member 2 is preferably smaller than the minor axis t1 of the inclusions 3a and 3b. In this case, when the cable is bent, the inclusions 3a and 3b can be prevented from passing through the gaps (clearances) c1 and c2, and the movement of the inclusions 3a and 3b to the inside of the bending can be more reliably suppressed. be able to.

  In FIG. 10, two inclusions 3 a and 3 b are vertically attached to the outer periphery of the cylindrical member 2 in the cable longitudinal direction. The inclusions 3a and 3b are disposed separately between the protrusions 5a and 5b. The inclusions 3a and 3b are impregnated with a resin such as urethane, and are thus integrated while suppressing the fluff of fibers while having flexibility.

  Since the other configuration of the optical fiber cable according to the fifth embodiment of the present invention is the same as that of the first embodiment of the present invention, the redundant description is omitted.

  At the time of intermediate branching of the optical fiber cable according to the fifth embodiment of the present invention, the length (projection amount) by which the blade of the tool is inserted inside the outer cover 5 is set so that the cylindrical member 2 is not damaged. In addition, the protrusions 5a and 5b of the outer jacket 5 are adjusted to a length that can be cut, or slightly shorter than that, and are extracted. Even when the outer cover 5 is cut into a circle with a tool blade, even if the protrusions 5a and 5b remain without being cut slightly, the cross-sectional area of the remaining portion is so small that it can be pulled and cut.

  According to the optical fiber cable according to the fifth embodiment of the present invention, the strength members 6a and 6b are embedded in the jacket 5 and the strength member 6a, as in the first embodiment of the present invention. , 6b, FRP can be used to cut the strength members 6a, 6b together with the outer cover 5 at the time of the opening operation, so that the opening operation can be easily performed.

  Here, as shown in FIG. 7, in the structure in which the inclusions 3a to 3d are vertically attached to the cylindrical member 2 and the outer cover 5 is not provided with a projection, as described above, when the cable is bent, bending distortion is caused. Accordingly, as shown in FIG. 8, the inclusions 3 a to 3 d may approach one side (bending side). As a result, it is conceivable that the cable core is decentered and the center core is damaged when the jacket 5 is cut. On the other hand, according to the fifth embodiment of the present invention, as shown in FIG. 10, since the projections 5a and 5b are provided on the inner side of the jacket 5, the inclusions 3a and 3b are bent inward. Movement can be suppressed. As a result, the eccentricity of the cable core can be avoided, and good leadability can be maintained.

  The manufacturing method of the optical fiber cable according to the fifth embodiment of the present invention is that the projections 5a and 5b are also formed when the outer jacket 5 is extruded using an extruder. Different from the embodiment. Since other procedures are the same as those of the first embodiment of the present invention, a duplicate description is omitted.

<Example>
As an optical fiber cable according to an example of the fifth embodiment of the present invention, an optical fiber cable having a structure as shown in FIG. 10 was produced. A cylindrical member (loose tube) 2 filled with jelly made of PBT was extruded on the optical fiber 1 to obtain an outer diameter of 1.9 mm. Two glass fiber bundles having a minor axis of 0.4 mm, a major axis of 2.5 mm, and a 1500 denier were wound around the periphery as inclusions 3a and 3b. Around the periphery, two glass FRPs having a diameter of 0.7 mm as the tensile strength members 6a and 6b were embedded in parallel in a jacket 5 made of linear low density polyethylene (LLDPE). The inner diameter of the jacket 5 is 2.8 mm, the outer diameter is 5.4 mm, and the thickness is 1.3 mm. Protrusions 5a and 5b having heights h1 and h2 of 0.3 mm are provided in the jacket 5.

  When the produced fiber optic cable was subjected to an extraction operation using a coaxial cable stripper manufactured by IDEAL as an extraction tool, the outer cover 5 in which the FRP was embedded could be easily cut in the circumferential direction. . At this time, the length inserted into the outer jacket 5 of the blade was adjusted to 1.5 mm. Further, the inclusions 3a and 3b and the loose tube 2 were left, and the extraction of 1 m or more was easily possible. Further, no scratch was observed on the surface of the cylindrical member 2 taken out.

  Further, the sum c1 + c2 of the clearance (clearance) between the protrusions 5a, 5b and the loose tube 2 is 0.3 mm at the maximum, whereas the short diameter t1 of the inclusions 3a, 3b is 0.4 mm. Even when bent, the protrusions 5a and 5b could suppress the inclusions 3a and 3b from dropping, and the cable core was not decentered.

  On the other hand, as a first comparative example, a steel fiber having a diameter of 0.7 mm was used as a tensile body, and an optical fiber cable having the same structure as that of the example was manufactured. In the comparative example, the steel wire, which is a tensile body, cannot be cut.

  Further, as a second comparative example, an optical fiber cable having the same structure as that of the example was manufactured except that the inclusions were not impregnated with resin such as urethane. In the second comparative example, fine glass fibers were fused to the outer cover, and the outer cover embedded with FRP could be cut, but the outer cover could not be pulled out.

(Sixth embodiment)
As shown in FIG. 11, the optical fiber cable according to the sixth embodiment of the present invention includes plastic films 4a and 4b vertically provided between the inclusions 3a and 3b and the outer jacket 5, and the inclusions. The point that 3a, 3b is not impregnated with resin such as urethane is different from the fifth embodiment of the present invention.

  As a material of the plastic films 4a and 4b, a thermoplastic resin such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT) or nylon (registered trademark), or thermosetting such as epoxy Resin can be used.

  The plastic films 4a and 4b may be fused to the outer cover 5 by heat or the like during extrusion molding of the outer cover 5, or may be adhered to the outer cover 5 using an adhesive or the like. 5 may not be fused or bonded. In the case where the plastic films 4a and 4b are fused or bonded to the outer cover 5, it is possible to cut the plastic films 4a and 4b at the same time as the outer cover 5 is cut during the opening operation. For this reason, it is not necessary to separately process the plastic films 4a and 4b after the outer cover 5 is pulled out as in the case where the outer cover 5 is not fused or bonded, and the workability is excellent.

  Since the other configuration of the optical fiber cable according to the sixth embodiment of the present invention is the same as that of the first embodiment of the present invention, the redundant description is omitted.

  At the time of intermediate branching of the optical fiber cable according to the sixth embodiment of the present invention, the length (projection amount) by which the blade of the tool is inserted inside the outer cover 5 is set so that the cylindrical member 2 is not damaged. In addition, the protrusions 5a and 5b of the outer jacket 5 are adjusted to a length that can be cut, or slightly shorter than that, and are extracted. Even when the outer cover 5 is cut into a circle with a tool blade, even if the protrusions 5a and 5b remain without being cut slightly, the cross-sectional area of the remaining portion is so small that it can be pulled and cut.

  According to the sixth embodiment of the present invention, as in the first embodiment of the present invention, the strength members 6a and 6b are embedded in the outer jacket 5, and the FRP is used as the strength members 6a and 6b. By using it, it is possible to cut together with the outer jacket 5 at the time of the mouthing work, so that the mouthing work can be easily performed.

  Furthermore, since the projections 5a and 5b are provided on the outer jacket 5 as in the fifth embodiment of the present invention, the inclusions 3a and 3b can be prevented from moving inwardly. As a result, the eccentricity of the cable core can be avoided, and good leadability can be maintained.

  Further, by disposing the plastic films 4a and 4b between the inclusions 3a and 3b and the jacket 5, the inclusions 3a and 3b are interposed by the plastic films 4a and 4b without impregnating the resin such as urethane. It is possible to prevent the objects 3a and 3b and the jacket 5 from being fused. The inclusions 3a and 3b may be impregnated with a resin such as urethane.

<Example>
An optical fiber cable having the structure shown in FIG. 11 was produced as an optical fiber cable according to an example of the sixth embodiment of the present invention. The plastic films 4a and 4b having a thickness of 16 μm and a width of 3.5 mm were vertically attached to the inclusions 3a and 3b. As the inclusions 3a and 3b, 2000 denier PP yarns that were not impregnated were used. Other structures and dimensions are the same as those of the first embodiment of the present invention.

  In the optical fiber cable according to the example of the sixth embodiment of the present invention, by disposing the plastic films 4a and 4b, fusion between the inclusions 3a and 3b and the jacket 5 is avoided, and good lead-out property is achieved. Was secured. In addition, good bendability was ensured even after the optical fiber cable was bent.

(Other embodiments)
As described above, the present invention has been described according to the first to sixth embodiments. However, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  For example, in the fourth and sixth embodiments of the present invention, the case where the two protrusions 5a and 5b and the two inclusions 3a and 3b are provided has been described, but the number of protrusions and the number of inclusions are not particularly limited. For example, as shown in FIG. 12, an even number (four) of protrusions 5a to 5d may be provided, and four inclusions 3a to 3d may be disposed between the protrusions 5a to 5d, respectively. Further, when there are three or more protrusions 5a and 5b, it is preferable that they are arranged at equal intervals, but they may be arranged at different intervals.

  As described above, the present invention naturally includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

DESCRIPTION OF SYMBOLS 1 ... Optical fiber 2 ... Cylindrical member 3a-3d ... Inclusion 4,4a, 4b ... Plastic film 5 ... Outer sheath 5a-5c ... Protrusion 6a, 6b ... Strength body

Claims (9)

Optical fiber,
A cylindrical member made of plastic covering the periphery of the optical fiber;
An inclusion made of fibrous plastic or glass fiber disposed around the cylindrical member and impregnated with resin;
A jacket covering the periphery of the cylindrical member and the inclusion;
A tensile body made of a pair of reinforcing fiber plastics embedded in the jacket with the optical fiber interposed therebetween ,
A plurality of protrusions are formed inside the outer jacket,
The cross section perpendicular to the cable longitudinal direction of the inclusion is substantially elliptical,
Two projections of the plurality of projections are in positions facing each other across the optical fiber,
An optical fiber cable , wherein a sum of gaps between each of the two protrusions and the cylindrical member is smaller than a minor axis of the inclusion . Optical fiber,
A cylindrical member made of plastic covering the periphery of the optical fiber;
An inclusion made of fibrous plastic or glass fiber disposed around the cylindrical member;
A jacket covering the periphery of the cylindrical member and the inclusion;
A plastic film disposed between the inclusion and the jacket;
A tensile body made of a pair of reinforcing fiber plastics embedded in the jacket with the optical fiber interposed therebetween ,
A plurality of protrusions are formed inside the outer jacket,
The cross section perpendicular to the cable longitudinal direction of the inclusion is substantially elliptical,
Two projections of the plurality of projections are in positions facing each other across the optical fiber,
An optical fiber cable , wherein a sum of gaps between each of the two protrusions and the cylindrical member is smaller than a minor axis of the inclusion . The cross section of the inclusion perpendicular to the longitudinal direction of the cable is elliptical, the major axis of the inclusion is w1, the diameter of the cylindrical space inside the jacket is D1, the outer diameter of the cylindrical member is D2, The number of inclusions is n, and the minor axis t1 of the inclusion is t1 = (D1-D2) / 2.
And the circumferential length L1 of the circle formed by the inclusions in the cross section perpendicular to the cable longitudinal direction,
L1 = (t1 + D2) × π
When stipulating
L1> w1 × n> D2 × π
The optical fiber cable according to claim 1 or 2, wherein the relationship is satisfied. The optical fiber cable according to any one of claims 1 to 3 , wherein two of the plurality of protrusions are provided on a straight line connecting the pair of strength members. The optical fiber cable according to any one of claims 1 to 4 , wherein the cylindrical member is one of a plastic tube and a plastic tape vertically or roughly wound. The optical fiber cable according to any one of claims 1 to 5 , wherein the inclusion has a heat resistance higher than that of the jacket. The optical fiber cable according to any one of claims 1 to 6 , wherein a plurality of the inclusions are arranged. An optical fiber, a cylindrical member made of plastic covering the periphery of the optical fiber, an inclusion made of fibrous plastic or glass fiber disposed around the cylindrical member and impregnated with resin, and the cylindrical shape An intermediate post-branching method for an optical fiber cable, comprising: a jacket covering the periphery of the member and the inclusion; and a tensile body made of a pair of reinforcing fiber plastics embedded in the jacket with the optical fiber interposed therebetween. ,
Inserting a blade into the jacket;
A step of rotating the blade inserted into the jacket in a circumferential direction of the jacket to cut the strength member and cutting the jacket into a ring. Branch method. An optical fiber, a cylindrical member made of plastic covering the periphery of the optical fiber, an inclusion made of fibrous plastic or glass fiber disposed around the cylindrical member, and the cylindrical member and the inclusion A jacket covering the periphery of the substrate, a plastic film disposed between the inclusion and the jacket, and a tensile body made of a pair of reinforcing fiber plastics embedded in the jacket with the optical fiber interposed therebetween. An intermediate post-branching method for an optical fiber cable comprising:
Inserting a blade into the jacket;
A step of rotating the blade inserted into the jacket in a circumferential direction of the jacket to cut the strength member and cutting the jacket into a ring. Branch method.

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